The aim of the program is to study the physiology, pharmacology, pathology, epidemiology, and clinical picture of heart disease in the young, principally in the patient with cogenital heart disease. The clinical aspects of the projects concern themselves with the incidence, mortality, and clinical course of congenital malformations of the heart, as well as the diagnosis by various invasive and non-invasive methods, particularly echocardiography. Pathologic studies, on a large number of heart specimens from this institution, as well as other centers from all over the world, aim at elucidating the embryologic origins of the malformations. In addition, morphologic studies of the pulmonary vasculature are being undertaken, in part as diagnostic tools for the quantitation of pulmonary vascular obstruction, and in part to increase our understanding of the nature of pulmonary vascular disease under a variety of physiologic conditions. The pharmacologic studies, by means of telemetry, in grown dogs and fetal as well as newborn lambs, aim at analyzing the mechanisms of action of a variety of agents particularly vasoconstrictors as well as the reflex control of the circulation at varying ages. Finally, physiologic studies on isolated, donor profused, dog and rat heart preparations are used to investigate the development and regression of cardiac hypertrophy as well as the electrophysiologic mechanisms underlying a variety of arrhythmias. BIBLIOGRAPHIC REFERENCES: Johnson, D. H., Rosentha., A., and Nadas, A.S.: A forty year review of bacterial endocarditis in infancy and childhood. Circulation 51: 581, 1975.